Re: [PATCH] video: da8xx-fb: preserve display width when changing HSYNC

From: Tomi Valkeinen
Date: Tue Aug 26 2014 - 08:38:09 EST


On 03/07/14 16:46, Ian Abbott wrote:
> When looking at this driver for a client, I noticed the code that
> configures the HSYNC pulse clobbers the display width in the same
> register. It only preserves the MS part of the width in bit 3 and zeros
> the LS part of the width in bits 9 to 4. This doesn't matter during
> initialization as the width is configured afterwards, but subsequent use
> of the FBIPUT_HSYNC ioctl would clobber the width.
>
> Preserve bits 9 to 0 of LCD_RASTER_TIMING_0_REG when configuring the
> horizontal sync.
>
> Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
> ---
> I haven't tested this change, but it's pretty trivial.
> ---
> drivers/video/fbdev/da8xx-fb.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/video/fbdev/da8xx-fb.c b/drivers/video/fbdev/da8xx-fb.c
> index 788f6b3..10c876c 100644
> --- a/drivers/video/fbdev/da8xx-fb.c
> +++ b/drivers/video/fbdev/da8xx-fb.c
> @@ -419,7 +419,7 @@ static void lcd_cfg_horizontal_sync(int back_porch, int pulse_width,
> {
> u32 reg;
>
> - reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0xf;
> + reg = lcdc_read(LCD_RASTER_TIMING_0_REG) & 0x3ff;
> reg |= (((back_porch-1) & 0xff) << 24)
> | (((front_porch-1) & 0xff) << 16)
> | (((pulse_width-1) & 0x3f) << 10);
>

Thanks, queued for 3.17 fixes.

Tomi


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